1. Field of the Invention
The present invention relates to a printing sleeve, i.e., a cylindrical sleeve for a printing cylinder, the printing sleeve being made by a method applying at least one sheet of a thermoplastic elastomeric composition which is hardenable under the influence of light (a photopolymer) upon a surface formed by a cylinder, gas-permeable means being provided at the cylinder surface which extend at least along the entire inside and full width of the sheet applied upon the cylinder surface, in such a manner that the sheet is pressed against the cylinder surface with the aid of a decreased gas pressure so that, by applying the pressure in conjunction with heat, the sheet is secured to the cylinder.
2. Description of the Prior Art
Printing sleeves obtained by such methods have already been used in the art. For example, U.S. Pat. No. 4,381,961 issued on May 3, 1983 to Hendricus J. van der VELDEN (assignee: STORK SCREENS B.V.) describes the use of a cylindrical core whose outer surface is provided with channels extending from one to the other end face of the cylinder and as a result of which a gas inclusion is prevented from occurring. In another method, instead of a metal cylinder an inflatable core (U.S. Pat. No. 4,391,898 issued on July 5, 1983 to the same inventor, same assignee) is used which forms a temporary support for a thin-walled metal sleeve to which the photopolymer sheet is secured.
The present invention provides an improved printing sleeve made by a method which is different from the known method first mentioned herein which in practice has the drawback, however, that the core provided with the channels cannot be utilized as a carrier for sheet-shaped printing plates which are smaller than the full circumference and/or the full length of the cylinder. So far, the printing plates have been secured to the surface by means of double-face adhesive tape but the grooved cylinder surface precluded effective adhesion of the adhesive tape. This rules out the universal usefulness of such serrated roller cores.